Recent theoretical formulations of nonendogenous depression, in contrast to traditional approaches, have assigned cognitive factors a central etiological role. Two cognitive theories that have dominated the empirically-based literature are: (a) the cognitive distortion model, wherein a negative cognitive schema is presumed to be activated in relation to evaluatively negative events; and (b) the learned-helplessness model, which suggests that depressed individuals tend to perceive that response and outcome are independent. Different predictions suggested by these two models have recently been evaluated using an attribution of causality paradigm. The proposed research is designed to reevaluate the applicability of the attribution of causality paradigm to depression using veridical descriptions of problematic situations and depressive behaviors obtained from a target population of university students. A behavioral-analytic methodology will be used to directly sample representative problematic situations and behaviors related to depression. Depressed and nondepressed subjects will participate in what is ostensibly called a "computer-assisted measurement system" and will indicate the likelihood of engaging in a variety of depressive behaviors in relation to a number of descriptions of problematic situations. Ascription of causality following positive or negative evaluative feedback will be measured using rating scales, enabling a direct contrast between opposing predictions suggested by the two theoretical models.